PHILADELPHIA — This may well have been the game when we saw for the very first time what Joe Girardi’s best qualities as a manager really are. Girardi has spent an awful lot of his first postseason on the witness stand, asked to defend himself and his methods and his occasional heavy hands, bathed in the bright light of interrogation.

But the truth of it is, a manager’s strengths and weaknesses are rarely crystallized through the simple prism of moves made and moves skipped. We learned that with Joe Torre, saw the power of proper communication, witnessed how far earning absolute trust and respect can really go in a clubhouse. Torre won four titles that way. Girardi is now halfway to his first for employing the same tactic.

So much of this 8-5 Yankees victory in Game 3 of the 105th World Series can be attributed to a single word that Torre used to employ with both reverence and regularity: trust. There was a regular coterie of players Girardi would lean on in the regular season, an array of trusted lieutenants who helped get the Yankees to this cusp of paradise.

Both have had their struggles this postseason, to the point where it wasn’t an unreasonable question to ask if they shouldn’t have their places of prominence marginalized, or at least significantly reduced. Swisher hadn’t hit a lick all October; Chamberlain’s problem was the exact opposite: it seemed every time he chucked a pitch toward home plate, someone was hitting the tar out of the ball. Even his outs were uncomfortably loud.

Girardi sat Swisher for the first time in Game 2 Thursday night. He kept Chamberlain and his other wunderkind setup kid, Phil Hughes, in the bullpen in that same game, bypassing the bridge from A.J. Burnett to Mariano Rivera and using an express lane. Some managers see a hot hand, they play that hot hand as long as they can.

Girardi?

Well, a few hours before Game 3, a few hours before the rains came and pushed the start of the game to past 9 o’clock and ensured the Yankees would start a game in October and finish it in November for the second time in their history, Girardi had been asked how he’d evolved as a manager since his first tempestuous year in Miami in 2006.

“You learn a lot about people,” he said. “You learn a lot about how to wear different hats, what relationships mean and the importance of doing everything in your willpower to get the most out of your players, no matter what it really takes. You learn all those things.”

Part of that is understanding when a rest is just a rest and not a benching. Swisher was back in the lineup, and at first things didn’t go well. He flied out his first at-bat in the second, and in the bottom of the inning he seemed to give up on a ball off the bat of Pedro Feliz that he might’ve been able to catch had he taken a better route.

More October miseries. And you could hear the snickers everywhere.

Then, something funny happened: With the Yankees having sliced a 3-0 lead to 3-2, Swisher led off the fifth with a double that hugged the third-base line. It was his second extra-base hit of the postseason in 37 at-bats, and it set the stage for a three-run outburst that wrested the lead away from the Phillies for good. An inning later, he slammed a home run to left that added the first of three insurance runs, his second RBI of the playoffs.

Suddenly Girardi wasn’t a stubborn martinet refusing to alter his thinking; he was a loyal skipper who’d danced with the girl who brung him. Same deal with Chamberlain, who came into a three-run game in the eighth facing 1, 2 and 3 in the Phillies lineup, and he blitzed through Jimmy Rollins, Shane Victorino and Chase Utley on nine pitches.

The playoffs can be such a wonderful laboratory for redemption. All it takes is one swing, or one strikeout, and you can induce amnesia on the masses. Alex Rodriguez proved that — or re-proved it — in the fourth, when he hit an opposite-field homer that clanged off an out-of-use TV camera and changed the tenor of the game — and instantly made everyone forget the 0-for-8, six-strikeout strait jacket he’d brought into it.

Let the people all forget. Girardi will do the remembering. He’ll stick with his guys.